INTRODUCTION:

Asparagus racemosus Willd. belonging to the family Asparagaceae is a climber found all over India, especially in Northern India. The roots of this plant is extensively used as an antidiarrhoeal, diuretic, aphrodisiac, antispasmodic and nutritive ¹. The roots also possess as an immuno adjuvant potential ², ulcer protective ³ and an antitussive ⁴. Since no scientific reports are available on antimicrobial properties of this medicinal plant, the present investigation is carried out to find out the antimicrobial activity. The antibacterial and antifungal activities of the roots were estimated by disc diffusion method. The minimum inhibitory concentration (MIC) was also determined. Further, the nutritive claims of the roots were justified by the nutritional analysis of the medicinal plant.

MATERIALS AND METHODS:

Plant collection and Extraction

The roots of Asparagus racemosus was collected from the outskirts of Chennai during April 2008 and identified and authenticated by Dr. Sasikala Ethirajulu, Research Officer (Pharmacognosy), Central Research Institute for Siddha, Chennai, Tamil Nadu, India.

The roots were washed in running water to remove the adherent soil particles and dried in shade. The powdered root was extracted with methanol (MEAR). The extract was reduced to a dark colored molten mass by removing the solvent in a rotary vacuum evaporator (Yield: 23.42 %) The coarse dry powder was used as such for nutritional analysis, the extract for antimicrobial activities.

Determination of Phytoconstituents

Preliminary phytochemical screening was performed as per standardized procedure ^{5, 6}. The various phytoconstituents in the methanol extract were identified.

Antimicrobial Screening

The extract (MEAR) was subjected to antibacterial (S. aureus, B. cereus, E. coli and P. aeruginosa) and antifungal (A. niger and C. albicans) screening. The antimicrobial screening was performed by agar diffusion method using a paper disc ^{7, 8}. The sterilized (autoclaved at 120^oC for 30 min) medium (40-50^oC) was inoculated (1ml/100ml of medium) with the suspension of the microorganism (matched with McFarland barium sulphate standard). The paper impregnated with the extract (250 and 500 µg/ml in dimethyl sulphoxide) was placed on the solidified medium. The plates were preincubated for 1 h at room temperature and incubated at 37^oC for 24 and 48 h for antibacterial and antifungal activities respectively. Gentamicin (10 µg/disc) and Ketoconazole (10 µg/disc) were used as standards for antibacterial and antifungal activities respectively. The observed zone of inhibitions is presented in Table 1.

Table 1: Zone of Inhibition and Minimum Inhibitory Concentration of Asparagus racemosus Willd. roots

Organisms Standard Zone of Inhibition (mm) MIC (mg)

MEAR (250 µg) MEAR (500 µg)

S. aureus 32 16 21 19

B. cereus 28 16 18 20

E. coli 38 16 21 21

P. aeruginosa 36 17 22 21

A. niger 30 20 21 17

C. albicans 32 22 26 16

Table 2: Nutritional content of Asparagus racemosus Willd. roots

Sl. No.	Nutritional principles	Values / 100 g of root powder
1.	Carbohydrate	16.78%
2.	Protein	10.56%
3.	Fat	0.0013%
4.	Moisture	4.04%
5.	Vitamin- A	12.45 IU
6.	Vitamin- D₃	2.56 IU
7.	Vitamin- E	1.056 mg
8.	Vitamin- K	0.023 mg
9.	Thiamine	1.234mg
10.	Riboflavin	0.245 mg
11.	Vitamin- C	27.67 mg
12..	Calcium	32.56 mg
13.	Iodine	0.047 mg
14.	Magnesium	54.12 mg
15.	Potassium	5.02 mg
16.	Phosphorus	0.12 mg
17.	Sodium	5.02 mg
18.	Copper	0.15 mg
19.	Iron	3.12 mg
20.	Manganese	0.35 mg
21.	Zinc	2.98 mg
22.	Selenium	BDL
23.	Antimony	BDL
24.	Cadmium	BDL
25.	Chromium	BDL
26.	Cobalt	BDL
27.	Arsenic	BDL
28.	Mercury	BDL

BDL: Below Detectable levels.

Minimum Inhibitory Concentration

The MIC for the above organisms was found by Agar streak dilution method ⁹. Nutrient agar was used for bacterial pathogens and Sabouraud’s dextrose for fungal strains. The media were sterilized by autoclaving at 15 lbs/sq inch pressure for 20 min. Stock solutions of the extracts were mixed with the known quantity of molten sterile agar media aseptically to provide the required concentrations. About 20 ml of the media containing the extract was poured into each sterile Petri dish and allowed for solidification. Thereafter Microorganisms were streaked one by one on the agar plate aseptically. After streaking all the plates were incubated at 37±1^oC for 24 and 48 h for antibacterial and antifungal activities respectively. Then the plates were observed for the growth of the microorganisms. The lowest concentration of the plant extract required for inhibiting the growth of the microorganism was considered as the MIC of the extract against bacterial and fungal strains. The MIC values of each extract against the tested microorganisms are presented in the Table 1.

Nutritional Analysis

The amount of carbohydrate, protein, fat, crude fibre, minerals and vitamins were determined for every 100 g of dry powder of A. racemosus. The amount of moisture, crude fibre and fat were determined by standardized procedure ¹⁰. Proteins ¹¹, calcium and magnesium ¹² and sodium ¹³were also estimated. Other trace elements were determined by Atomic-Absorption Spectroscopy (Perkin Elmer 2380)¹⁴. Few vitamins were estimated as per the procedure of Indian Pharmacopoeia ¹⁵and thiamine using the procedure of United States Pharmacopoeia ¹⁶. All the values are presented in Table 2.

RESULTS AND DISCUSSION:

The preliminary phytochemical screening was carried out on the methanol extract of A. racemosus indicated that the presence of various phytoconstituents such as alkaloids, carbohydrates, proteins, amino acids, phenolic compounds and flavanoids. The antimicrobial screening implied that the extract was highly effective against the fungal organisms

than that of the bacterial strains, which is indicating that this is a potential source for antifungal drug (Table 1). The antibacterial activity observed as moderate. In the determination of MIC, the concentration of extract for the cessation of growth of the fungal organisms were needed lower than that of the bacterial organisms. The nutritive principles determined were tabulated and indicated that the roots of A. racemosus can be a suitable alternative for providing necessary nutrients to pregnant women, lactating women, young children and Geriatrics (Table 2).

From the above observed findings, it becomes evident that the drug A. racemosus conforms as a potential antifungal agent and also posses a good role in the management nutritional deficiencies in all age groups and genders, when administered in a suitable composition.

REFERENCES:

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Received on 14.05.2009 Modified on 11.07.2009

Research J. Pharm. and Tech.2 (4): Oct.-Dec. 2009; Page 777-779